The technique for changing a display portion from a vertically long display to a horizontally long display in a conventional mobile information terminal of this type, for example, a mobile phone, is disclosed in, for example, Japanese Patent Laying-Open No. 2003-319043 (Patent Document 1). FIG. 144 is a schematic front view showing a configuration of a mobile phone disclosed in the aforementioned publication. With reference to FIG. 144, this mobile phone 510 has a lower unit 510, an upper unit 502 and a hinge portion 503. Lower unit 501 and upper unit 502 are joined in a foldable manner through hinge portion 503. Lower unit 501 has an operation portion 511 formed of a variety of keys. Upper unit 502 has a display portion unit 502a having a display portion 521 and a support portion unit 502b rotatably and slidably supporting display unit 502a. 
This mobile phone 510 is changed from a folded state (not shown) of lower unit 501 and upper unit 502 to an open state (FIG. 144(a)) by rotating upper unit 502 around hinge portion 503 with respect to lower unit 501. In this state, display portion 521 is vertically long display. From this open state (FIG. 144(a)), display portion unit 502a is rotated with respect to support portion unit 502b thereby to bring display portion 521 into the horizontally long display. Furthermore, display portion 502a is slid toward lower unit 501 with respect to support portion unit 502b thereby to bring about the states shown in FIGS. 144(b)-(d).    Patent Document 1: Japanese Patent Laying-Open No. 2003-319043